An invisible connection between two notation elements that can be traversed by some command.
See also diagram.
A notation on a piece of paper contains no hidden information. A notation on a computer screen, however, may contain additional invisible hyperlinks that are not apparent in a static view but that can be invoked dynamically to access some other piece of information, either in a graphical view or in a textual table. Such dynamic links are as much a part of a dynamic notation as the visible information, but the UML specification does not prescribe their form. They are a tool responsibility. The UML specification attempts to define a static notation for UML, with the understanding that some useful and interesting information ...